Belt abrasive machine



Jan. 24, 1928.

C. SEEL BELT ABRASIVE MACHINE Filed Nov. 23, 1925 3 Sheets-Sheet l Znvenion Jan. 24, 1928 C. SEEL BELT ABRASIVE MACHINE Filed Nov. 23, 1925 3 Sheets-Sheet 2 C. SEEL BELT ABRASIVE MACHINE Filed'Nov. 25, 1925 s Sheefs-Sheet "3 to the Patented Jan. 24, 1928.

UNITED "STATES n CARL SEEL, 01' ST. GAJZILIZI, SWITZEBLAI ND.

BELT ABRASIVE mnonrim.

Application filed November 23, 1925,.Serial No. 70,845, and in Switzerland November .29, .1924.

The known machines for sanding by means of a traveling abrasive belt for instance profiled bars of any material pre sent the disadvantage that only profiled bars having simple wide profile surfaces can be smoothed as for guiding the abrasive belt disproportionately large guidances are required so that the possibilities of utilizing these machines are very limited.

\Vith the machine according to the present invention these disadvantages are overcome inasmuch as the abrasive belt is caused to assume a shape that approximates the shape needed in the operative part of the belt in contact with the molding block pressing the belt against the work to be smoothed, by the provision of guide members arranged in front and at the rear of the molding block and causing the abrasive belt to assume .a tubular shape and furtherby means of elements arranged intermediate of the molding block and of said guide members, said elements in cooperation with said guide members cause the abrasive belt to be brought into a shape that approximately corresponds profile at the molding block whereby the belt is spread and shaped, and stresses are produced within the belt which tend to keep it in its operative position in front and at the rear of the operative place.

constructional examples of the subject matter of the present invention are illustrated on the accompanying drawings in which Fig. 1 is a front elevation of the belt abrasive machine,

Fig. 2 is a side elevation seen from the right in Fig. 1,

Fig. 3 shows 111 a side elevation and partly in section the moulding block and the means for holding it in position, r

Fig. i is a front elevation with parts shown in section of Fig, 3, i

Fig. 5 is a horizontal section along line VV in Fig. 1,

Fig. 6 is a section along line VIVI in Fig. 1.

Fig. tail,

Fig. 8 is a front elevation of the belt abrasive machine shown in Figs. l-7 provided with an apparatus for smoothing reentering edges,

7 shows the tubular guidance in de- Fig. '9 is a front elevation on a larger scale of this apparatus,

10 is a section along line X ,X in' Fig. 9, i i F ii is .a'section along line XI-XI in Fig. 10, p i

Fig. 12 is a side elevation of the means for actuating the apparatus and i Fig. 13 shows a detail in elevation.

At the rear side of the hollow standard of the machine is fixed a bracket '2 inwhich the driving shaft 3 is rotatably mounted. The driving shaft carries the driving pulley 4, the loose pulley 5, the step pulley 6 and a small driving pulley '7. i A pedestal hearing 8 is fixed to the top of the standard 1 in which the shaft 11 carrying the step P111. 1 ,7 9 and the pulley 10 is rotatably mount 12 denotes the belt connecting the step pulleys '6 and 9. i

The table 15 is .hingedat 18 (Fig. 6 to a slide 17 which is adjustable in the vertical direction along the-standard 1 in a known manner by means of the screw threaded spindle 16 the hinge joints 18 permitthe table to be inclined in the downward direction and to be adjusted into any desired inclined position. To this end segment shaped supports 19 are pivoted to the table 15,and are providedwith a curved .slot with which screws 20 cooperate whereby the table may be fixed in any inclined position,

21 denotes the work. consisting in the present case of a. molded bar, which is placed on the table 15 so that the molded surface points inthe u ward direction and the -bar rests 011 the eed rollers 22, 22 which project slightly above the table; lateral guide rails vrection of the table and fixed to the latter by means of screws 25 cooperating with .transverse slots 24:, guidethe bar 21. The isu pports 26 which are adjustable in the vertical direction carry rollers .27 adapted to press the work against the feed rollers 22 22".

The feed roller 22 mounted on the vshaiit31 is 23, which are adjustable in the transverse dii rollers is ensured with any inclination of the table 15. The pulley 28 is driven from the pulley 7 by means of the belt 33. Above the table 15, the carrier arms are fixed to the standard 1; the arms 35 are provided with longitudinal slots; angular brackets 36 are fixed to said arms and are laterally adjustable along the arms and in the vertical direction. To these angular brackets 36 the tubular guide members 38, 39 are secured and a longitudinal slot 37 in said brackets permits an adjustment of said guide members relatively to said brackets 86. Each guide member is provided with a longitudinal slot 43 (Fig. 7) by means of which the endless abrasive belt 40 may be inserted in the guide member. The abrasive belt 40 passes over the driving pulley 10 the outer surface of which may be provided with a rubber coating to increase the frictional driving contact with the belt and the latter passes over the pairs of guide and tension pulleys 41 and 42 to the guide members 38 and 39. Obviously the tubular guide members 38 and 89 may be replaced by one or more rings. To the angular bracket 45 which is fixed to the standard 1 and which is adjustable in the vertical direction, a plunger 46 is secured which acts as guide to a hollow cylinder l7 (Figs. 3 and 1). The rod 48 passes through the bottom of the cylinder 4.7 and the upper end of the rod is guided in a bore of the plunger '16 whilst to the lower end of the rod 48 a head 49 is screwed which carries the molding block 50 the profile of which is the complement of the profile of the bar to be smoothed. The rod 48 is rigidly connected to the cylinder 7 and the molding block 50 is continuously pressed against the work by the action of a helical spring 51, whereby the abrasive belt 40 which is guided below the molding block between the guide members 38 and 39 is pressed in a resilient manner corresponding to the force of the spring against the work 21. The abrasive belt 40 travels in the direction of the arrow P indicated in Fig; 1. It has now been found that the known disproportionate guidances may be dispensed with if the abrasive belt on its part near the work is caused to assume and to maintain at least approximately the shape which it takes up below the molding block. This is obtained by causing the abrasive belt to be bent to a tubular shape by the guide member 38 before it reaches the point where it operates on the work, and by the guide member 39 after that operative point and by providing between said guide members 38 and 39 and the molding block 50 further guide bodies preferably rollers 52, 5st. These guide bodies cause to a reater or lesser extent a momentary fiattenlng of the abrasive belt to which the tubular guide members have imparted a tubular shape, whereby the belt is also secured against a lateral displacement, and the belt tends to assume again the tubular shape so that iuternal stresses are generated across the belt which cause the latter to readily assume a shape which corresponds or very nearly cor responds to the profile of. the molding block already before it reaches the latter. The molding block has thus not the task ol shaping the belt :ua-ording to its profile but it serves mainly to improve the shape of the belt which is already preformed and to press the latter against the work. 'lhcrcby it is possible to use a molding body of an approximately simple design and to grind or sand any desired profile with great accuracy. After the belthas passed the guide member 39 it spreads itsell automatically by run ning over the tension pulley 42.

In order to sand complicated profiles such as heretofore had to be finished by milling tools, many eiqierimenls have been necessary, and I have discovered that by trans vcrsely curving the belt to cylindri al shape and then passing the bell over a pulley just before it reaches the molding block the belt will assume the shape of the block more accurately, so that l an: enabled to sand pro files ha 'ing small radii ol curvature that form fillets either concave or convex of the profile shapes.

From my observation of a great many experiments I believe that this novel phe nomenon is due to the :t'ollowing: The belt curved transversel to a maximum extent, i. 0.. to a cylinder, has a natural tendency to flatten and then rover its cu rvaturc in rapid succession after a certain distance from the guide member that gives it its cylimlrical form. The belt. so to say, in rapid transverse motion. and the distance from the guides at which such action takes place do pends upon the material. of the belt, its width, thickness, speed and tensiolu conse quently the guide rollers and 54; that tend to flatten the belt must be adjustable to and from the point oi. ahrading contact.

lVhile the rollers 51? and 5-1: tend to flatten the belt and prevent reverse curvature. the speed of the bolt permits the rollers to act only momentarily to damp the traiuvcrsc movement so that the persistence oi the transverse movemcul is carried past the rollers by the speed oi. the belt to the mold, and by reason of the rapid. now damped, vibration of low amplitiule, the belt rapidly and very much more accurately conforms to the profile of the mold.

This discovery I believe to be new. but whether my explanation oi. the cause of the novel action is. corrmzt or not, I have found that my construction embodying the tubular guides 38, 3t). and the rollers M, 52 gives unusual results; the belts last longer and do not have so pronol'uiccd a. temlency to split.

The guide body or roller 5:2 is mounted in lllll Jan tion oft the teed roller :22; preferably the Work is so positioned that the outermost lateral edges of the work are at thesame elevation which is effected with some :profiles by turning the table 15 into an inclined direction. A molding body 50 the profile of which is the complement of the profile of the Work to be sanded is then screwed to the head 49 andythe abrasive belt is passed between the molding block 50 and the Work; the rollers and 5-Cland the tubular guide lnembers 38 and 39 are then so adjusted that the abrasive belt 40 assumes approximately the profile ot' the molding block, and the latter and the table are then so adjusted that the abrasive belt is slightly pressed against the Work. l-Vh-en the drive of tie machine is cut in the Work is passed below the abrasive belt by the action of the feed rollers 22 and 522 and the rollers 27 in opposite direction to that of the operative part of the belt but at a much slower speed than that of the abrasive belt.

Figs. 813 illustrate an additional apparatus provided on the belt abrasive machine and utilized for sanding edges and particularly re-entering edges of the Work.

To the carrier arm 35 a casing 56 is secured in an adjustable manner by means of the bracket 57 and screw bolt58. A shaft 59 mounted in the rear Wall of the casing, carries a crank disc 60 havin a crank pin 61. The latter is in engagement With a body 62 fixed to a rod 63 which is guided in the casing and is thus reciprocated by the rotating shaft 59. A frame 64 is fixed to said rod 63 by means of bolts 65 and the frame is provided with vertical guidanccs 66, 67 in which a plate 68 is slidably mounted. Springs 69 acting on bolts 70 tend to press the plate 68 in the downward direction. On the plate (58 a further plate 71 is adjustably fixed and endless abrasive bands 72 and 73 are placer. around the plate 71 and fastened to the latter by means of a Wedge 74-. Preferably one of the abrasive bands will bear a coarse abrasive material and the other a fine abrasive material. The lower edge 75 of the plate 71 is shaped ac cording to the particular portion of the moldedbar 21 which has to be smoothed by the reciprocating apparatus. In the example illustrated a re-enteringedge, which the abrasive belt 40 can only exactly smooth by causing excessive stresses in the abrasive belt is conveniently and accurately smoothed by means of the apparatus. Obviously the lover edge of the plate 71 may have any other shape.

lhe shaft 59 is driven from the driving shaft 3 of the machine by means of a cord pulley 76 mounted on the latter, a :cord T7 and a cord pulley 7S fixed to a shalt T9, the latter being rotatably mounted in a bracket 80 secured to the standard 1 of the machine. Zetween the shaft '79 -.lnd the shaft 59 an intermediate shaft 81 provided with two universal joints 852 and S3 is interposed to ensure a proper driving connection with the apparatus adjusted in any position relatively to the molded work to suit a particularly molded work to be acted upon.

The abrasive bands 72 and 73 may conveniently be shifted for replacing their Worn parts situatedat the operative edge of the plate '51, the wege '7 permitting the convenieut shitting or the complete replacement of the abrasive bands 72 and 78.

I claim:

, l; A belt abrasive machine, comprising combination, an abrasive belt, a table for supporting the Work, a plurality of guide and tension pulleys over which said belt passes, a molding block engaging the back of said belt and pressing the latter against the Work, tubular guide members through Which said belt passes and arranged on both sides of said molding block, and further guide means interposed between said tubular guide members and the molding block and adapted to momentarily flatten to some extent the belt to which a tubular shape is imparted by said tubular guide means so that it readily assumes the shape. of the molding block.

:2. A belt abrasive machine, comprising in combination an abrasive belt, a table for supporting the Work, a plurality of guide and tension pulleys over which said belt travels, a molding block engaging the back of said belt,'resilient means acting on said molding block for pressing the latter against the Work, tubular guide members through which said belt passes, arranged on both sides of said molding block and securing the traveling abrasive belt against displacements in the transverse direction, and further guide means interposed between said tubular guide members and the molding block and adapted to momentarily flatten to some extent the belt to which a tubular shape is imparted by said tubular guide means so that it readily assumes the shape of the molding face.

3. ll belt abrasive machine, comprising in combination, an abrasive belt, a table for supporting the Work, a plurality of guide and tension pulleys over which said belt travels, a molding block engaging the back of said belt, resilient means acting on said molding block for pressing the latter against the Work, tubular guide members through which said belt pass adjustable in the vertical and lateral directions and arranged on both sides of said molding block and securing the traveling abrasive belt a ainst displacements in the transverse direcrmn, and further adjustable guide means interposed between said tubular guide members and the molding block and. adapted to momentarily llatten to some extent the belt to which a tubular shape is imparted by said tubular guide means so that it readily assumes the shape of the molding taco.

4. A belt abrasive machine comprising in combination a staiulard, a slide adjustable in the vertical direction along said standard, a table for sup iorting the work and hinged to said slide, means adapted to iii: said table in any inclined position relatively to said slide, an abrasive belt, a plurality oiiguide andieir sion pulleys over which said belt tra 'els. a molding block engaging the back ot said belt, resilient means acting on said molding block for pressing the latter against the Work, tubular guide members through which said belt passes, arranged on both sides of said molding block and securing the traveling abrasive belt against displacements in the transverse direction, and further guide means interposed between said tubular guide members and the molding block and adapted to momentarily flatten to some extent the belt to which a tubular shape is imparted by said tubular guide means so that it readily assumes the shape of the molding face.

A belt abrasive machine, comprising in combination, a standard. a s ide adjustable in the vertical direction alon said standard, a table for supporting the work and hinged to said slide. means adapted to fix said table in any inclined position relatively to said slide, an abrasive belt, a plurality ol guide and tension pulleys over which said belt travels, a molding block engaging the back of said belt, resilient means acting on said molding block for pressing the latter against the Work, tubular guide members provided with a slot for the insertion of the abrasive i; and arranged on both sides ol said mold ing block and securing the traveling abt'lisive beltagainst displacement in the transverse direction, and further guide means inter- 'iosed between said tubular guide members and the nmlding lJlOlfli and adapted to momentarily flatten to some extent the belt to which a tubular shape is imparted by said tulmlar guide means so that it readily assumes the shape of the molding face.

In testimony whereof, I have signed my name to this specification.

CARL SEEL. 

